Drop-pit apparatus



Aug' 24, 1943- R c. ORTGIES, I 2,327,446

DROP -PIT APPARATUS Filed April s., 1943 4 sheets-sheet 1 muy y m Aug. 24, 1943. a. c. oR'rGlEs DROP PIT'APPARATUS Filed April 3, '1945 4 Sheets-Sheet 2 Aug. 24, 1943. R. c. oRTGlEs DROP PIT APPARATUS` Filed April s, 1943 4 Sheets-Sheet 5 Aug-.2.4, 1943. R. c. oR'rGlEs 2,327,446

DROP PIT APPARATUS Filed April :5, 1943 4 sheets-sheet 4 Patented Aug. 24, 1943 DROP-PIT APPARATUS Raymond C. Grtgies, Chicago, Ill., assigner tor Whiting Corporation, Harvey, Ill., a corporation of Illinois Application'April 3, 1943, Serial No. 481,675

1G Claims.

The invention relates to drop-pit apparatus.

In servicing and repairingrthe under-equipment of vehicles, such as automotive buses, trackless trolley cars, street cars and trucks, it is necessary to lift body springs, under floor motors,

iiierential housings, transmissions or other parts.

One object of the invention is to provide droppit apparatus which includes a lifting screw which is adapted to' be transported longitudinally and laterally in the pit to center the screw for lifting under parts in different locations on the vehicle, so that a single jack may be used for lifting under-equipment located on different portions of the vehicle.

Another object of the invention is to provide drop-pit apparatus .which is adapted for general lifting purposes in connection with the servicing and repair of parts of the under-equipment of the vehicle and includes interchangeable xtures on the lifting mechanism for engaging the parts of different character so that a single jack Will be usable for lifting any ofthe parts.

A still further object of the invention is to provide drop-pit mechanism which is useful generally for lifting any of the'under-equipment of the vehicle, is simple in construction, and facilitates the Work of inspection, repairV or removal and replacement.

Other objects of the invention will appear from the detailed description.

The invention consists inthe several novel features which are hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a longitudinal section of drop-pit apparatus embodying the invention.

Fig. 2 is a plan of the carriage which is adapted to travel longitudinally of the pit and the lifting jack which is adapted to travel on the carriage transversely of the pit, the sides of the pit being shown in section. I

Fig. 3 is a transverse section illustrating in full lines the jack-screw in position for lifting one of the body supporting springs oi the vehicle and in dotted lines the jack-screw and the fixture for engaging the differential housing on the vehicle,

Fig. 4 is a transverse section through the lifting mechanism.

Fig. 5 is a section taken on line 5 5 of Fig. 4.

Fig. 6 is a perspective of the longitudinally movable Wheeled carriage.

Fig."7 is a perspective of the fixture used forengaging and lifting a lea-f spring on thevehicle.

Fig. 8 is a perspective of the xture used for engaging a differential .housing on the vehicle.

Fig. 9 is a perspective of the fixture used for engaging the front axle of `a truck.

Fig. 10 is a perspective of the fixture used for engaging an under-licor motor or a transmission on a vehicle.

Theinvention is exemplified with a .iioor I5 beneath which is built a drop-pit I6, over which the .Vehicle a is `adapted to travel and which is of suiiicient length for access to substantially all portions of the under-equipment of the vehicle. The floor is provided with inwardly extending ledges or portions Il which define the opening at the top and overhang the inner faces of the side walls I8 of `the pit. These overhanging ledges make 'the pit Wider than the top opening through which the lifting mechanism is movable to engage the under-equipment on the vehicle. The spacesunder the ledges I1 provide areas at the sides of the pit for sufficient transverse travel oi the lifting mechanism for engaging any of the equipment on the vehicle overlying said opening. Channel girders I9 extend longitudinally the full length of the pit and are secured to the pit walls I8, which are usually of concrete, by suitable anchors 2B. Wood beams 2l t in the channel girders IS and space said girders from the side Walls of the pit, and channel standards 22 additionally support the girders I9 from the bottom of the pit. The top flanges of girders I9 serve as rails which form a track extending longitudinally the full length of the pit and are disposed under the ledges I'l.

The drop-pit apparatus comprises a wheeled truck or carriage which is adapted to travel longitudinally on the girders lEI and lifting mechanism on a Wheeled carriage which is adapted to travel transversely on the longitudinally movable carriage, so that the lifting mechanism may be moved longitudinally and crosswise of the pit into a position to engage the equipment on any part of the vehicle over the top of the pit.

The longitudinally movable carriage comprises side-plates 23 which are rigidly cross-connected by a pair of channel girders 24, axles 25 mounted in the end portions of the plates 23, and Wheels 26 are journaled on said axles. The Wheels at each end of the side-plates 23 are rigidly cross-connected by sleeves 2l. The Wheels 26 are ilanged and are adapted to travel on the longitudinal girders I9 so that this carriage can be moved longitudinally to any portion of the pit l5. The top anges of channel girders 24 serve as a pair of transverse rails which are spaced apart to form a transverse track.

The apparatus comprises a transversely movable carriage which is adapted to travel crosswise of the pit on the cross girders 24 of the longitudinally movable carriage. This carriage comprises a casing 30 which serves as a transversely movable carriage frame. The casing 33 comprises a body section 35 which forms a gear housing and a cover section 38 removably secured by screws 37 to said body section, The body section 35 has a pair of spaced integral bracket members 32 at each of its ends. An axle 3d is journaled in each pair of bracket members 32 and a pair of flanged wheels 3| is secured to each axle. Wheels 3l are adapted to travel on the top iianges of the girders 24 of the longitudinally movable carriage. The lower portion of casing 33 is adapted to travel between the cross girders 24. A jack-screw 33 extends vertically through the casing 30, is vertically shiftable by a worm gear 3S which is journaled on a thrust-bearing 4B, and conned against vertical movement in the casing 30. The hub of gear 39 has screw-threaded engagement with the jack-screw 38 so that rotation of said gear inene direction will raise the screw, and rotation in the opposite direction will lower the screw. The upper end of screw 38 is provided with a thrust-shoulder lll and a ring 4la on said shoulder, and a stud-extension 42 above the shoulder for interchangeably intertting with lifting fixtures as hereinafter described. The screw S8 extends below the casing 33 and is there housed by a tube 43. The upper end of tube 53 extends into and is fixed to a depending tubular extension 44 on the bottom of the body 35 of the gear casing. The lower end of tube 43 is closed by a cap 45. The tube 43 is adapted to contain oil for lubricating the jackscrew 38 and has connected thereto a filler pipe 33a through which the tube may be'lled up to the line of the pipe. The screw 38 is slidably held against rotation by studs 33a which are secured in the tube 43 and extend into a vertical groove 38h in said screw. A drain-plug 49 is provided in the cap l5 on the end of tube 43. The casing 3i] is adapted to retain oil for lubricating the gearing therein and a pipe 48 is connected thereto for introducing oil into the casing.

Worm-gear 38 in the casing 3U, is provided with an upwardly extending hub which is journaled in a bushing 4S held in the cover section 36 of the casing 3D. 'Ihe screw 38 is Aguided in a bushing 4l which is fixed in the body-section 35 of casing-33. Worm-gear 39 is engaged by a worm U on the shaft 5| which is journaled in heads 52 in the sides of the body-section 35 of casing 33. One end of shaft 5l extends through one of the caps 52 and a belt-pulley 53 with V-grooves is fixed to said shaft for driving the gearing to raise and lower the screw 38. A reversible electric motor 54 is mounted on a depending bracket 55 which is secured to the body-section 35 of gear casing 30. A belt pulley 55a with V-grooves is fixed to the shaft 56 of motor 5s and drives V-belts El which extend into and around V-grooves and drive the pulley 53.

A head 63 for supporting work-engaging xtures is removably secured to the stud 42 on the upper end of screw 38 and is provided with a socket 3l for receiving the upper end 42 of said shaft. 'I'he depending hub on head 60 is adapted to rest on the thrust ring Ma on the screw 38. A fitting 54 for engaging a differential housing on the vehicle ts on the lifting head 60 and comprises a base plate 65, upwardly extending end members 3B provided with semicircular notches El for receiving the tubular extension on the sides of the differential housing, reinforcing ribs 65a, and a ring 68 on the under side of base 65 for receiving the head 63 and confining the fixture 64 against lateral movement on the head. The several parts of fixture 64 are formed of plate metal and are welded together. The base plate has reinforcing downwardly extending flanges G9. This exemplifies removable fixtures engageable by the head 60 on the jack-screw for engaging a differential housing,

A fixture 'i0 is provided for engaging the front axle of a truck for lifting it for removal, inspection or repair of the king-pins of the dirigible wheels. The fixture 10 comprises a base 1l, end members I2 provided with notches 13 for receiving the axle, side flanges I4 and a ring I5 on the under side of base 1I which is adapted to removably receive, and fit around, the head 60 on the screw 38. These parts are formed of plate metal welded together. This exemplifies a 1fixture for engaging a non-rotatable truck ax e.

A fixture 'l'l is provided for engaging an under-floor motor or a transmission housing on the vehicle. This fixture comprises a base plate 18, side flanges 79 and a ring 80 on the under side of plate 78 for receiving the head 60 on the jack-screw, all welded together. This exemplifies a fixture for engaging a motor or transmission housing on the vehicle.

A xture or saddle 82 is provided for engaging 'a body spring on the vehicle, and comprises a base 83, side iianges 84 and a hub S5 which is provided with a socket 86 which is adapted to receive the upper end 42 of the jack-screw when the head 60 is removed. This exemplifies a fixture for engaging the body spring of a vehicle.

A switch 39 is included in the circuit of the motor 54 when the worm 50 is driven to raise the jack-screw 38. The enclosing box of said switch 89 is secured to 'a plate 89a which is supported from the body-section 35 of the casing 30. Switch 89 is adapted to be opened to interrupt said circuit by a rock shaft 90 to which is secured an arm 9|. A spring-pressed stud 9|Ct is slidably mounted in the depending portion 44 of the bodysection 35 of the casing 3U and is shiftable by a cam 92 on a plate 93 which is fixed to a plate secured to the lower end of the screw 33. When screw 38 is raised to its high limit, cam 52 will push the stud 9|a outwardly to rock arm 9i and shaft 90 and open the switch 89. This device is mounted on the transversely movable carriage and automatically limits the upward movement of the screw 38 by the operation of the motor 54. A switch 94 is secured to the plate 89a on the casing section 35 and is included in the circuit for operating the motor 54 to drive worm 53 in the direction in which it will lower the screw 38. 'This switch 94 comprises a rock shaft 96 which has affixed thereto an arm 5. A rod 97 is mounted for vertical sliding movement in a lug on the body-section 35 and is normally pressed upwardly by a spring 98. The lower end of rod 91 is adapted to engage the arm 95 to open the switch 94. A rigid arm 38 on the upper end of rod 91 is extended to be engaged by the ring Ma or the nxture on the upper end of screw 38 when the latter reaches its predetermined low limit. 'This exemplies means mounted on the transversely movable carriage for automatically controlling the lower-ing movement of the screw 38.

The operation of the apparatus will be `as fol lows: The vehicle will be positioned over the opening in the floor at the top of the pit as illustrated in Fig. The longitudinally movable carriage can be wheeled to any desired position longitudinally of the pit to the point where `an element on the vehicle is to be raised. The transversely movable `carriage can be wheeled transversely to the point desired 'according to the transverse location of the 4part on the vehicle to 'be lifted.A If the dilerential housing is tobe lifted, the lxture 64 .is placed on top `of the head lit. The motor 54 will then be :operated to drive the worm 5l and rotate .gear 39 for raising the screw 318 to the extent desired to support the housing in its raised position for the performance of any work thereon. rlhe motor .34 can also be operated in reverse direction to lower the screw 38 and the engaged differential housing. When a front axle with dirigible wheels is to be lifted, the ring of fixture T0 will be placed around the lifting head 60 and the screw 3B may be raised and lowered as before described.

When 'an under-floor motor or transmission casing is to be lifted, the ring 8 on fixture 1l will be placed around the lifting head 60 and the motor 5t may be raised and lowered as before described.

When a body spring is to be lifted, the lifting head 8E is removed from the upper end d2 of the lacie-screw and the fixture 82 is placed on the upper end of said shaft with the iixture in abutting engagement with the thrust-ring 41a. The motor can then be operated to raise and lower the screw 38 as before described. During any of these operations the screw 38 will be stopped at the predetermined high and low limits. When the cam 92 strik-es the stud Sla, arm 9i will be shifted to rock shaft 9i] fand open the switch 89 for the circuit in which the motor 511 is included. During the lower-ing operation, the thrust-ring tia or the hub 85 on xlture 82 will depress arm 98 and ro-d 91 to shiil-l the arm 95 and rock shaft 96 to open the switch 84 and the circuit for the motor during the lowering operation .of the jack-screw.

The invention exemplifies drop-pit apparatus in which the jack-screw is mounted on `a transversely movable carriage which in turn is mounted on a longitudinally movable carriage so that .the jackscrew may be brought into operative position under a part to vbe raised, which is located `trans-- versely or longitudinally on any part of the vehicle over the pit. It also exemplies apparatus of this type which includes interchangeable -iixtures for engaging diierent parts of the underequipment of the vehicle, such as diferential housings, front axles, under-licor motors, transmissions and springs. The apparatus is simple in construction and elcient in operation.

The invention is not to be understood as restricted to the details set Vforth since these may be modified with-in the scope of the appended claims without departing from the spirit and scope of the invention.

Hav-ing `thus described the invention, what I claim as new and desire to Vsecure by Letters Patent is:

1. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over -a vpit extending longitudinally beneath `the vehicle,

CII

comprising longitudinal rails fixed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and -to travel longitudinally of thefpit on said longitudinal rails, transverse rails on the longitudinally movable carriage, extending substantially across the pit, a wheeled carriage mounted Ito travel on the transverse rails for movement across the pit, a vertically extending jack-screw mounted for vertical movement in the `transversely movable oarria'ge and having its upper end extended for lifting, and .mechanism for raising and lowering the screw, mounted on and to travel with the transversely movable carriage, the screw and said mechanism being movable to different transverse and longitudinal positions in the pit by 'transverse and longitudinal lmovements of the carriages, respectively.

2. Apparatus for raising land lowering parts of the equipment on a vehicle disposed over .a pit extending longitudinally beneath the vehicle, comprising longitudinal rails xed along the `sides and elevated above 'the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally `of the pit on said longitudinal rails, rails on the longitudinally movable carriage extending transversely :substantially vacross 'the pit, a wheeled carriage mounted to travel on the transverse rails 'for movement across the pit, a single vertically extending jack-screw mounted for vertical movement in the `transversely movable carriage, Va part-engaging element on the up- .pei` end of the screw, and mechanism for raising and lowering the screw, mounted on and "to travel withthe transversely movable carriage, the screw and said mechanism being movable to different transverse and longitudinal positions the pit by transverse vand longitudinal movements of the carriages, respectively.

S. Apparatus for raising fand lowering parts -of the equipment on fa vehicle disposed over a pit extending longitudinally beneath the vehicle and provided yat the floor with inwardly overhanging ledges, comprising longitudinal rails fixed along the sides, elevated above 'the bottom of the pit and underlying the ledges, a wheeled carriage mounted on and to travel longitudinally of the pit on said longitudinal rails, transverse rails on the longitudinally movable carriage extending substantially across the pit, a wheeled carriage mounted to travel on the transverse rails for movement across the pit, Ia vertically extending jack-screw mounted for vertical movement in the transversely movable carriage and having its upper :end extended for lifting, and mechanism for raising land lowering 'the 'screw mounted on and to travel with the *transversely vmovable carriage, the screw 'and said mechanism bei-ng movable to different transverse and longitudinal positions in the .pit by transverse and longitudinal movements of the carriage, respectively.

4. Apparatus ior raising and lowering parts of the equipment on ra vehicle disposed over a pi-t extending longitudinally beneath ithe vehicle, comprising longitudinal rails iixed along the sides and 'elevated above the bottom :of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on said longitudinal rails, rails on the longitudinally movable carriage extending transversely ksubstantially across the pit, a wheeled carriage mounted to travel on the transverse rails for :movement `across the pit, Va single vertically extending jack-screw mounted between theA rails on the .longitudinally movable carriage, and having its upper end extended for lifting, and mechanism for raising and lowering the screw mounted on and to travel with the transversely movable carriage, the screw and said mechanism being movable to dilerent transverse and longitudinal positions in the pit by transverse and longitudinal movements of the carriages, respectively.

5. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath Athe vehicle, comprising longitudinal rails xed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails and comprising longitudinally extending end plates and transverse girders between the end plates and extending substantially across the pit, and provided with rail forming upper surfaces, a carriage provided with wheels on the transverse girders for movement across the pit, a vertically extending jack-screw mounted for vertical movement in the casing between the transverse girders and having its upper end extended for lifting, and mechanism for raising and lowering the screw and mounted to travel with the casing, the screw and said mechanism being movable to different transverse and longitudinal positions in the pit by transverse and longitudinal movement of the carriages, respectively.

6. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails iixed along the sides and elevated above the bottom of the pit, a c

wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails and comprising longitudinally extending end plates and transverse girders between the end plates, extending substantially across the pit and provided with rail-iorming surfaces, a carriage provided with wheels on the transverse girders for movement across the pit, said transversely movable carriage comprising a casing, a vertically extending jack-screw mounted for vertical movement in the casing between the transverse girders and having its upper end extended for lifting, and mechanism comprising gearing in the casing, ior raising and lowering the screw and mounted to travel with the casing, the screw i and said mechanism being movable to diierent transverse and longitudinal positions in the pit by transverse and longitudinal movement of the carriages respectively.

7. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails xed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally or the pit on the longitudinal rails, transverse rails on the longitudinally movable carriage, extending substantially across the pit, a wheeled carriage mounted to travel on the transverse rails for movement across the pit, said transversely movable carriage comprising a casing, a vertically extending jack-screw mounted for vertical movement in the casing between the transverse rails and having its upper end extended for lifting, gearing in the casing for raising and lowering the screw, an electric motor for driving said gearing, mounted on the casing, the screw, gearing and motor being movable to dilerent transverse and longitudinal positions in the pit by transverse and longitudinal movement of the carriages, respectively.

8. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extendingr longitudinally beneath the vehicle. comprising longitudinal rails xed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails and provided with rails extending substantially across the pit, a carriage comprising a gear-casing provided with extensions and wheels on said extensions, mounted to travel on the transverse rails for movement across the pit, a vertically extending jack-screw mounted for vertical movement in the casing between the transverse rails and having its upper end extended for lifting, and mechanism comprising gearing in the casing for raising and lowering the screw and mounted on and to travel with the casing, the screw and said mechanism being movable to diflerent transverse and longitudinal positions in the pit by transverse and longitudinal movement oi the carriages, respectively.

9. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails xed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally oi the pit on the longitudinal rails, transverse rails on the longitudinally movable carriage extending substantially across the pit, a wheeled carriage mounted to travel on the transverse rails, a single jack-screw mounted for vertical movement in the transversely movable carriage, a liiting head on the upper end of the screw, mechanism carried by the transversely movable carriage for raising and lowering the screw, and xtures for engaging different parts of the equipment on a vehicle interchangeably and removably mounted on the head.

10. Apparatus for raising and lowering parts oi' the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle,

comprising longitudinal rails fixed along the sides and elevated above the bottom of the pit, g wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, transverse rails on the longitudinally movable carriage extending substantially across the pit, a wheeled carriage mounted to travel on the transverse rails, a single jack-screw mounted for vertical movement in the transversely movable carriage, and having its upper end extended for lifting, mechanism carried by the transversely movable carriage for raising and lowering the screw, and fixtures for engaging different parts of the equipment on a vehicle interchangeably and removably mounted on the upper end of the screw.

ll. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails fixed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, transverse rails on the longitudinally movable carriage extending substantially across the pit, a, wheeled carriage mounted to travel on the transverse rails, a single jack-screw mounted for vertical movement in the transversely movable carriage, and having its upper end extended for lifting, mechanism carried by the transversely movable carriage for raising and lowering the screw, and forked iixtures for engaging different parts of the equipment on a vehicle interchangeably and removably mounted on .the upper end of the screw.

12. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails xed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, transverse rails on the longitudinally movable carriage extending substantially across the pit, a wheeled carriage mounted to travel on the transverse rails, a single jack-screw mounted for vertical movement in the transversely movable carriage, a lifting head on the upper end of the screw, mechanism carried by the transversely movable carriage for raising and lowering the screw, and a fixture for engaging a part of the equipment on a vehicle, provided with a socket for removably receiving the head.

13. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails fixed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, said longitudinally movable carriage comprising rails extending substantially across the pit, a wheeled carriage mounted to travel on the transverse rails for movement across the pit, said transversely movable carriage comprising a casing, a vertically extending jack-screw mounted for vertical movement in the casing between the transverse tracks and having its upper end extended for lifting, a tubular housing for the jack-screw on the casing and extending substantially to the bottom of the pit, means on the housing for holding the screw against rotation, and gearing in the casing for raising and lowering the screw, the screw and said housing being movable to different transverse and longitudinal positions in the pit by transverse and 1ongitudinal movement of the carriages, respectively. n

14. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit4 extending longitudinally beneath the vehicle' comprising longitudinal rails fixed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, said longitudinally movable carriage comprising rails extending transversely of and substantially across the p it, a wheeled carriage mounted to travel on the transversely extending rails for movement across the pit, said transversely movable carriage comprising a casing, a vertically extending jack-screw mounted for vertical movement in the casing between the transversely extending rails and having its upper end extended for lifting, a tubular housing for the jackscrew on the casing and extending substantially to the bottom of the pit, means on the housing for holding the screw against rotation, gearing in the casing for raising and lowering the screw, and a motor for driving the gearing, mounted on the housing, the screw, motor and said housing being movable to diiferent transverse and longitudinal positions in the pit by transverse andv longitudinal movement of the carriages, respectively.

15. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails fixed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, said longitudinally movable carriage comprising rails extending transversely of and substantially across the pit, a wheeled carriage mounted to travel on the transversely extending rails for movement across the pit, said transversely movable carriage comprising a casing, a vertically extending jack-screw mounted for vertical movement in the casing between the transversely extending rails and having its upper end extended for lifting, gearing in the casing for raising and lowering the screw, an electric motor for driving the gearing, limit-switches for the motor, mounted on the casing, and means controlled by the upper and lower ends of the screw for shifting the limit-switches, the screw and said housing being movable to different transverse and longitudinal positions in the pit by transverse and longitudinal movement of the carriages, respectively.

16. Apparatus for raising and lowering parts of the equipment on a vehicle disposed over a pit extending longitudinally beneath the vehicle, comprising longitudinal rails xed along the sides and elevated above the bottom of the pit, a wheeled carriage mounted on and to travel longitudinally of the pit on the longitudinal rails, said longitudinally movable carriage comprising rails extending transversely of and substantially across the pit, a wheeled carriage mounted to travel on the transversely extending rails for movement across the pit, said transversely movable carriage comprising a casing, a vertically extending jack-screw mounted for vertical movement in the casing between the transversely extending rails and having its upper end extended for lifting, gearing in the casing for raising and lowering the screw, an electric motor for driving the gearing, limit-switches for the motor, mounted on the casing, a member controlled by the upper end of the screw and mounted on the casing for shifting one of the limit-switches and a member on the lower end of the screw and. in said housing, for shifting the other limitswitch, the screw and housing being movable to different transverse and longitudinal positions in the pit by transverse and longitudinal movement of the carriages, respectively.

RAYMOND C. ORTGIES. 

